How much physiology is needed in forest gap models for simulating long-term vegetation response to global change? Challenges, limitations, and potentials

Gap models were introduced over 30 years ago to examine the dynamics of for est vegetation structure and species composition based on plant population dynamics. While there have been many advances, gap models remain heavily cr iticized for their lack of attention to physiology, particularly as it affe cts their ability to simulate forest response to elevated CO2 concentration and climatic change. In this paper we provide a summary and synthesis of t he results from the Gap Model Comparison Workshop that was held in July, 19 99 at Pingree Park, Colorado (U.S.A.). We identify some grand challenges fo r the future development of forest gap models and discuss limitations as we ll as potentials of this modeling approach.